Among the runners Hollon beat to the finish line was Karnazes, who finished nearly 90 minutes later.

Of Hollon's feat, Karnazes said, “It's just remarkable. At 19, the last thing on my mind was spending hours and hours running in the middle of nowhere. I was focused on college. I was chasing women. I wasn't chasing Badwater buckles.”

There is no prize money at Badwater. Runners who finish in 48 hours or less earn silver belt buckles.

Karnazes said he does worry that Hollon might be doing harm to his body. Just to qualify for Badwater, Hollon ran 207 miles combined in two races during a six-week span late last year.

To guard against injury and burnout, Hollon said in the future he'll limit himself to one 100-mile race a year. He's not wasting any time establishing a new challenge. Although he's never ridden a bike farther than 80 miles, he wants to enter next October's Furnace Creek 508, the 508-mile bike ride that starts in Santa Clarita and passes through the Mojave Desert and Death Valley.

“I want to show I'm not just a runner,” said Hollon, who has run a 3:04 marathon, fast enough to qualify for the Boston Marathon.

There is irony to Hollon achieving long-distance fame. He ran varsity cross country at Poway High but admits he was not on the best of terms with his coach.

Hollon wasn't passionate about the sport then. He acted in school plays. He dabbled in triathlon. He skipped some practices to go on longer runs with friends.

Said Hollon, “I can imagine him opening the paper or looking at an ultrarunning magazine, seeing my face on the cover and saying, ‘That damn, kid.’ ”